Traditionally, camera cranes and dollies have been employed to assist in the positioning of cameras at defined locations and orientations to capture the desired shot. (For the purpose of this application a camera shall refer to any type of device capable of recording or transmitting either still or moving images including but not limited to conventional cinema cameras, conventional still cameras, television cameras, videotape cameras, digital cameras, CCD cameras, or the like.) Conventional camera cranes are generally comprised of a crane arm (or “jib”), a support structure to which the crane arm is mounted, and a “leveling head” affixed to the distal end of the crane arm. Typically, the crane arm is pivotally coupled to the support structure in a manner that facilitates the rotation of the crane arm about a vertical and a horizontal axis. The rotation of the crane arm about the vertical axis is generally referred to as crane arm “swing,” while the rotation of the crane arm about the horizontal axis is generally referred to as crane arm “boom.” In addition to the crane arm being capable of swing and boom, conventional crane arms are often constructed to be adjustable in length, so that the crane arm can “telescope” from one length to another. Thus, the distal end of the crane arm (i.e., the end affixed to the leveling head) is capable of translating through a semi-sphere, the diameter of which is controlled by the overall length of the crane arm, which can be adjusted by telescoping the crane arm. Moreover, camera cranes are often mounted on a rolling platform that is generally referred to as a “dolly.”
The leveling head is a mechanism that is typically employed to connect the camera crane arm to a camera mounting structure referred to as a “camera head.” Leveling heads are generally comprised of a leveling mechanism that functions to maintain a “leveling plate” parallel to a defined plane in response to changes in the boom of the crane arm. As used in this application a “leveling plate” is a defined member of the leveling head that is adapted to being coupled to the camera head. An example of such a leveling head is disclosed in U.S. Pat. No. 4,943,019, which is hereby incorporated herein by reference in its entirety for all purposes.
A camera head (a.k.a. remote head) may then be mounted to the leveling head. Conventional camera heads, in addition to providing a support structure to securely mount the camera, are typically adapted to rotate about a vertical axis (i.e., panning) and a horizontal axis (i.e., tilting) relative to the leveling plate. To facilitate the panning and tilting of the camera head, two independently actuated motor mechanisms are usually employed. The first is often referred to as a “camera pan motor,” which as the name suggests facilitates the panning of the camera head (i.e., the rotation of the camera head about the vertical axis). The second is often referred to as a “camera tilt motor,” which also as the name suggests facilitates the tilting of the camera head (i.e., the rotation of the camera head about the horizontal axis).
In operation, the boom (i.e., the rotation of the crane arm about a horizontal axis), swing (i.e., the rotation of the crane arm about a vertical axis), telescope (i.e., the length of the crane arm), and the movement of the rolling platform or dolly are typically controlled manually by one or more operators or “grips.” The adjustments of the leveling head are usually automated to respond to the change in the boom so as to maintain the camera head generally level to the horizontal plane. The “pan” and “tilt” of the camera head together with the focus of the camera, on the other hand, have been traditionally controlled remotely (usually via electrical circuitry) by another operator, referred to as the “camera-operator,” who is responsible for the composition of the shot (i.e., the field of view and focus of the camera).
FIG. 1 is a perspective view of an exemplary conventional camera positioning system 100. Shown in FIG. 1 is camera support structure 102 capable of movement with multiple degrees of freedom. Camera support structure 102 can include movable platform or dolly 104, crane arm support structure 106 mounted on the dolly, telescoping crane arm 108 pivotally mounted to the crane arm support structure, and leveling head 110 mounted to distal end 112 of the crane arm. Camera head 148 can be mounted to leveling head 110, and can include camera mounting bracket 152 upon which camera 154 can be mounted.
Dolly 106 can include base structure 114 to which crane arm support structure 106 is mounted. To facilitate movement of dolly 104, base structure 114 can include two axles 116 (shown in phantom), with each axle having two wheels 118 mounted thereto. Dolly sensing device 120 can be employed to monitor the movement of dolly 104 and transmit, via suitable communication means, data relating to the movement of the dolly to processing system 122 (shown in phantom in FIG. 1). For the purposes of this description, “suitable communications means” can include electrical, electro-magnetic, optical, mechanical or any other means suitable for transferring data between the sensing device and the processing system employed. Also for the purposes of this description, “movement” can include the act, process, or result of moving.
Crane arm 108 can mounted in a suitable fashion to crane arm support structure 106 via coupling mechanism 124. Coupling mechanism 124 can facilitate, via rotatable support shaft 130, the rotation of crane arm 108 about a vertical axis, which in FIG. 1 corresponds with the axis called out as Zw, so as to permit changes in the swing angle of the crane arm. In addition, coupling mechanism 124 can facilitate, via horizontal pivot 140, the rotation of crane arm 108 about a horizontal axis, which in FIG. 1 corresponds with the axis called out as Yw, so as to permit changes in the boom angle of the crane arm.
Crane arm swing sensing device 150 can be employed to monitor the swing (i.e., the rotation of the crane arm about the vertical axis) of the crane arm and transmit, via suitable communication means, data relating to crane arm swing to processing system 122 located in camera operator control module 156. Similarly, crane arm boom sensing device 160 can be employed to monitor the boom (i.e., the rotation of the crane arm about the horizontal axis) of the crane arm and transmit via suitable communication means data relating to the crane arm boom to processing system 122.
In exemplary system 100 illustrated in FIG. 1, swing and boom sensing devices 150, 160 can individually comprise a rotary encoder such as part number 8-5800-2146-5000 manufactured by Fritz Kubler GMBH of Germany. As illustrated in FIG. 1, rotary encoder swing sensing device 150 employed to monitor the swing of the crane arm 108 can be fitted to housing 126 of support structure 102 and monitor via a toothed belt the rotation of support shaft 130 relative to the housing. Similarly, rotary encoder boom sensing device 160 employed to monitor the crane arm boom can be mounted to the side wall of coupling mechanism 124 and monitor via a toothed belt the relative rotation of horizontal pivot 140. Each of encoder sensing devices 150, 160 can be adapted to transmit data relating to their respective monitored stimuli to processing system 122 via electrical communications transmitted through electrical cable 128.
Telescoping crane arm 108 can include nested sections 180A, 180B, and 180C configured so that each inner section is supported within the outer adjacent section. Extension of crane arm inner sections 180B, 180C can be controlled by means of crane arm telescope motor 170 mounted at the end of crane arm 108 opposite leveling head 110. Crane arm telescope motor 170 can supply drive via a cable and pulley mechanism such as that disclosed in U.S. Pat. No. 4,939,019, already incorporated by reference, so as to facilitate the extension and retraction of crane arm sections 180B, 180C.
A crane arm telescope sensing device 132 can be employed to monitor the telescope (e.g., length) of crane arm 108 and transmit, via suitable communication means, data relating to the crane arm telescope to processing system 122. In exemplary system 100 illustrated in FIG. 1, crane arm telescope sensing device 132 can include a rotary encoder, such as part number BDE 05.05A500 manufactured by Baumer Electric of Switzerland. As illustrated in FIG. 1, encoder telescope sensing device 132 can be mounted to the wall of crane arm section 180A and can be adapted to monitor via a toothed belt the rotation of drive shaft 134 of crane arm motor 170. Encoder telescope sensing device 132 can also be adapted to transmit data relating to the rotation of drive shaft 134 to processing system 122 via electrical communications transmitted through electrical cable 128.
Leveling head 110 can be removably coupled to distal end 122 of the innermost crane arm section 180C. Leveling head motor 136 can be mounted within the housing of leveling head 110 and drive a worm gear 138 that can be adapted to engage semicircular moon gear 142, the base of which defines leveling plate 144. In some embodiments, level sensor 146, such as a mercury tilt switch, can be fitted to worm gear 142 just above leveling plate 144 and can be electrically connected to leveling head motor 136. Level sensor 146 can be configured to activate leveling head motor 136 to maintain leveling plate 144 horizontal with respect to a defined plane (e.g., horizon, ground, etc.) in response to changes in the boom of crane arm 108. It should be understood, however, that other sensors, control systems and mechanical means well-known in the art can also be used to maintain leveling plate 144 in a desired configuration.
Typically, if leveling head 110 is needed in its conventional under-mount configuration, the leveling head can be mounted directly to distal end 112 of crane arm 108 as shown in FIG. 1. However, if leveling head 110 is needed in a top-mount configuration (e.g. to enable the camera to point upward and generally have a more unobstructed upward view), a separate top-mount bracket must first be attached to distal end 112 of crane arm 108 to enable the leveling head to be mounted with its leveling plate facing upward. Similarly, if leveling head 110 is needed in a front-mount configuration, a separate front-mount bracket must first be attached to distal end 112 of crane arm 108 to enable the leveling head to be mounted with a mounting plate facing forward (i.e. facing the same direction as the crane arm). The need for these separate mounting brackets causes a significant amount of time to be wasted while changing configurations. For example, to change a camera head from an under-mount to a top-mount configuration, the camera head must first be removed from the leveling head, and the leveling head must be removed from the crane arm. A top-mount bracket must then be installed in the crane arm. The leveling head can then be installed in the top-mount bracket, and the camera head can be installed on the leveling head. All of these steps can take a lot of time, which can represent a significant expense during filming, and also hinder the crane's performance and limit its versatility.
Therefore, there is a need for a mounting bracket that can be installed at a distal end of a crane arm to provide multiple mounting locations for one or more camera heads, lights, and the like, without any of the tradeoffs or compromises to performance.